New MySQL default Cast Rule for bit(1) to boolean, fix #93.

We need a new transformation function that work with a vector of
integers as input.

src/sources/mysql-cast-rules.lisp

@@ -66,6 +66,10 @@
 	     :target (:type "boolean" :drop-typemod t)
 	     :using pgloader.transforms::tinyint-to-boolean)
 
+    (:source (:type "bit" :typemod (= 1 precision))
+	     :target (:type "boolean" :drop-typemod t)
+	     :using pgloader.transforms::bits-to-boolean)
+
     ;; we need the following to benefit from :drop-typemod
     (:source (:type "tinyint")   :target (:type "smallint" :drop-typemod t))
     (:source (:type "smallint")  :target (:type "smallint" :drop-typemod t))

src/transforms.lisp

@@ -16,6 +16,7 @@
 		 date-with-no-separator
 		 time-with-no-separator
 		 tinyint-to-boolean
+		 bits-to-boolean
 		 int-to-ip
 		 ip-range
 		 convert-mysql-point
@@ -98,7 +99,13 @@
    tinyiny that are either 0 (false) or 1 (true). Of course PostgreSQL wants
    'f' and 't', respectively."
   (when integer-string
-   (if (string= "0" integer-string) "f" "t")))
+    (if (string= "0" integer-string) "f" "t")))
+
+(defun bits-to-boolean (bit-vector)
+  "When using MySQL, strange things will happen, like encoding booleans into
+   bit(1). Of course PostgreSQL wants 'f' and 't'."
+  (when (and bit-vector (= 1 (length bit-vector)))
+    (if (= 0 (aref bit-vector 0)) "f" "t")))
 
 (defun int-to-ip (int)
   "Transform an IP as integer into its dotted notation, optimised code from

test/parse/hans.goeuro.load

@@ -16,6 +16,10 @@ LOAD DATABASE
       -- override char(1) to varchar(1), just use char(1) here.
       type char when (= precision 1) to char keep typemod,
 
+      -- bit(1) is a boolean too!
+      -- it's a default setting, just shows how to type it in
+      type bit when (= precision 1) to boolean drop typemod using bits-to-boolean,
+
       column ascii.s using byte-vector-to-bytea,
       column enumerate.foo using empty-string-to-null